What is https://httpyac.github.io/ missing in comparison to postman, insomnia or hopscotch? I really like being able to run .http files as unit tests in ci as well as during debugging.
I would be happy to hear what you think of ownCloud Infinite Scale, a go microservice implementation of the ownCloud WebDAV and sharing APIs. We are limiting ourselves to file sync and share, but integrations with collabora and OnlyOffice are there. Just don't expect server side encryption. It was only added to the oc10 codebase to prevent storage admins to read the data. It does not protect against evil sysadmins in the least. Imo an encrypted filesystem or overlay filesystem can be used to solve that use case.
If you need E2EE cryptomator works just fine.
That being said, oCIS does add other things to the table: for an out of box experience we bundle a small OpenID Connect Identity provider that should suffice for a small home lab.
And we now support parts of the libre graph API, which is an effort to build a federated graph API closely following Microsoft Graph. Obviously, our team focuses on file sync and share, but e.g. the Kopano guys are working on the PIM parts.
The team is busy preparing the next release and customer projects based on the new stack, but we are happy with what we have achieved so far.